Vehicle movement control and detection method and apparatus

ABSTRACT

A vehicle movement control and detection system is divided into a plurality of vehicle control blocks, and the movement of a vehicle within a given vehicle control block is controlled by a vehicle control signal generated in the given vehicle control block. A signal receiver in the given vehicle control block senses the presence of a vehicle and a storage device stores a vehicle presence signal in response to the signal receiver sensing the vehicle presence. The storage device continues to store the vehicle presence signal until the vehicle has checked into the following vehicle control block. The generation of the vehicle control signal is prevented in the event the signal receiver no longer senses the vehicle&#39;&#39;s presence, or the storage device no longer stores the vehicle presence signal, during the time the vehicle is within the given vehicle control block, or in the event another vehicle is present in the succeeding vehicle control block.

United States Patent [191 Perry Jan. 9, 1973 [54] VEHICLE MOVEMENTCONTROL AND DETECTION METHOD AND APPARATUS [75] Inventor: Robert 11.Perry, Monroeville, Pa.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: Dec. 24, 1970 [21] Appl. No.: 101,333

[52] US. Cl. ..246/28 R, 246/63 C, 246/187 B [51] Int. Cl. ..B6ll 21/10[58] Field of Search ..246/187 B, 34 R, 63 C, 28 R [56] References CitedUNITED STATES PATENTS 3,227,870 l/1966 Joyce ..246/l87 B 3,202,8168/1965 Gregg.... ..246/63 C 3,045,112 7/1962 Hailes ..246/63 C 3,218,45311/1965 Bingham' 246/34 R 3,626,177 12/1971 Franke ..246/l R 3,041,4486/1962 Pascoe et a]. ..246/l87 B X Primary Examiner-Gerald M. ForlenzaAssistant Examiner-George H. Libman Attorney-F. H. Henson and R. G.Brodahl [57] ABSTRACT A vehicle movement control and detection system isdivided into a plurality of vehicle control blocks, and the movement ofa vehicle within a given vehicle control block is controlled by avehicle control signal generated in the given vehicle control block. Asignal receiver in the given vehicle control block senses the presenceof a vehicle and a storage device stores a vehicle presence signal inresponse to the signal receiver sensing the vehicle presence. Thestorage device continues to store the vehicle presence signal until thevehicle has checked into the following vehicle control block. Thegeneration of the vehicle control signal is prevented in the'event thesignal receiver no longer senses the vehicles presence, or the storagedevice no longer stores the vehicle presencesignal, during the time thevehicle is within the given vehicle control block, or in the eventanother vehicle is present in the succeeding vehicle control block.

10Clahns, 4 Drawing Figures BLOCK 3 ---BLOCK 1 ,lo )2 m4 0 87 K 51 1e)#500 a): 52cm 790, P); 58 52c me I l 1 SPEED SPEED j SPEED (f (fzmENCODER Ft ll (fzlR I ENCODER Fl il '2" ENCODER 1 H 1 I 1 J ,4J

use H60 ll6c CONTROL S|GNAL CONTROL SIGNAL CONTROL SIGNAL FR M L K 0FROM BLOCK FROM BLOCK 2 (REVERSE) (REVERSE) (REVERSE) FROM BLOCK4(RESETl r30): s 2 I340 380 1 I32c 34 I380 "8b 1 13Gb a l 0 I360 I240 )201366 C PEI 321A l36b +l I Q in l30c l+ S- c lu'ngj 1 if 1 I l i" 1 Y i22 H 24b 3 l22o v l I "Bi 9 |22c [2i i )3? .1 1 8). KO (RESET) 55 4 5lszuf i (CONTROL) To --;BLI I526 I54: BLOCKO BLO (CONTROL) Q %BL2 lRESET I CONTROL j jr VEHICLE FORWARD RUNNING |5o\ CONTROL DEVICE REVPATENTEDJAI -9 1915- SHEET 3 [IF 4 llallllllm xOOJQ VEHICLE MOVEMENTCONTROL AND DETECTION METHOD AND APPARATUS BACKGROUND OF THE INVENTIONGenerally, prior art vehicle control and detection systems utilized thesteel wheels of a vehicle to short circuit steel rails in which signalswere introduced, and thereby detected the presence of the vehicle. Thiswas a relatively simple control and detection operation wherein signalsare introduced from a signal source into the steel rails at one end of agiven vehicle control block and are sensed by a signal receiver attheother end of that same vehicle control block. If a vehicle is notpresent within a given vehicle control block, the signals introduced atthe one end of the vehicle control block, are sensed by the receiverlocated at the other end of the vehicle control block.

In the event a vehicle is within the given vehicle control block, thesteel wheels of the vehicle short circuit the signal in the steel rails,and the receiver located at the other end of the vehicle control blockis therefore unable to sense the signal, thus indicating the givenvehicle control block is occupied.

This type of vehicle control and detection system has a number offailsafe features in that a failure of the signal source, the signalreceiver, track breakage, or

any other of a number of failures result in the signal transmitted fromthe signal source not being received by the signal receiver. This isindicative of a vehicle control block being occupied, which is a safeoperational condition as no vehicle is allowed to enter the vehiclecontrol block under these conditions.

With the advent of transportation systems including rubber tiredvehicles, another failsafe type system must be devised for determiningthe presence of a vehicle within a given vehicle control block, as wellas devising a method to control the movement of the vehicle. Known priorart vehicle control and detection systems utilize a signal transmissionfrom a vehicle to a wayside receiver situated in the vehicle controlblock to generate a signal indicating that the vehicle control block ispresently occupied by a vehicle. This is less ofa failsafe vehiclecontrol and detection system, since the failure of the transmitter onboard the vehicle; failure of the signal receiver at the wayside; or thefailure of transmitting or receiving antennas, or any of a number ofsystem failures indicate that the vehicle control block is unoccupied asthe signal receiver no longer receives the signal transmitted by thevehicle. This is obviously an unsafe condition as it results in anindication of the vehicle control block being unoccupied, when in factthe vehicle control block is occupied by a vehicle. In such a situation,a following vehicle would be permitted to enter the occupied vehiclecontrol block resulting in a collision of the two vehicles which mayresult in derailment of one or both vehicles and possible injury to, orloss of life of persons on board the two vehicles. f

The teachings of the present invention utilize a signal transmissionfrom a vehicle in conjunction with a signal storage device located atthe wayside of a vehicle control block to indicate vehicle presencewithin the vehicle control block. In the event the signal transmitter onboard the vehicle fails or the signal receiver at the wayside fails, thestorage device continues to store a signal indicative of a vehicle beingpresent in the vehicle control block, which is a safe mode of operation.

SUMMARY OF THE INVENTION The present vehicle control and detectionmethod and apparatus is a system divided into a plurality of vehiclecontrol blocks, and the movement of a vehicle through a given controlblock is controlled by a vehicle control signal generated within thegiven, vehicle control block. In each vehicle control block there is adevice for sensing the presence of a vehicle within the block. A storagedevice stores a vehicle presence signal in response to the sensing ofthe presence of the vehicle with the given vehicle control block, andthe vehicle presence signal is stored until the vehicle checks into thefollowing vehicle control block. During the time the vehicle presencesignal is stored, a control signal is transmitted to the preceedingvehicle control block to prevent the generation of a vehicle speedcontrol signal within the preceeding vehicle control block. Thegeneration of a vehicle speed control signal in a given vehicle controlblock is prevented in the event the device for sensing the vehiclepresence no longer does so, or the storage device no longer stores thevehicle presence signal, during the time the vehicle is within the givenvehicle control block or the succeeding vehicle control block isoccupied by a vehicle. The devices utilized in a vehicle control block,may include either solid state or relay type devices.

DESCRIPTION OF THE DRAWINGS FIGS. 1A and 18 form a system block diagramembodying the teachings of the present invention for detecting andcontrolling the movement of a vehicle in either a forward or reversedirection;

FIG. 2 is a system block diagram embodying the teachings of the presentinvention for detecting and controlling the movement of a vehicle in aforward direction;

FIG. 3 is a system block diagram embodying the teachings of the presentinvention for detecting and controlling the movement of a vehicle in areverse direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In reference to theblock diagrams of FIGS. 1A and 13 there is shown, when the drawings areplaced end to I end, a vehicle detection and control system in which avehicle 2 (as shown in FIG. 1A) includes a front vehicle car 4 and arear vehicle car 6. The vehicle 2 may travel from left to right oralternatively from right to left over I a vehicle path 8 which isdivided into a plurality of vehicle control blocks which are illustratedas block 1, block 2 as shown in FIG. 1A of the drawings and block 3 asshown in FIG. 1B of the drawings. The division line between block 0 (notshown) and block 1 is schematically illustrated by the line 10, thedivision line between vehicle control block 1 and vehicle control block2 is indicated schematically by the line 12, and the division linebetween vehicle control block 2 and vehicle control block 3 is indicatedschematically by the line 14. The front vehicle car 4 (as shown in FIG.1A) includes a radio frequency transmitter 16 which transmits a signalat a frequency f1. over an antenna 18. The rear vehicle car 6 includes aradio frequency transmitter 20 which transmits a radio signal at afrequency f2 which is a frequency different than the frequency fl, andthe signals at frequency f2 are transmitted over an antenna 22.

The movement of the vehicle 2 in a direction from left to right(as-shown from FIG. 1A to FIG. 1B) is considered a forward movement ofthe vehicle and the movement of the vehicle from right to left isconsidered a reverse movement of the vehicle. The direction of travel ofthe vehicle may be controlled by a switch contained in the vehicle, orthe vehicles direction of travel may be controlled by a remote controldevice such as the control device 24 shown in FIG. 1B. A signal istransmitted via the antenna 26 to the vehicle if the vehicle is totravel in the forward direction and a signal is transmitted via theantenna 28 if the vehicle is to travel in the reverse direction. Thecontrol device 24 also sends a forward command digital signal via theline 30 to the vehicle control and detection logic circuit 33 containedin FIGS. 1A and 1B, and a reverse command digital signal is transmittedvia the line 32 to the vehicle control and detection logic circuits ofFIGS. 1A and 1B. The function of these signals is explained in detaillater in the specification.

Refer briefly to the schematic illustration of the control device 24 inFIG. 1B which is one of many control devices suitable for use in thepractice of the present invention. The control 7 device 24 includes NPNtransistors 34 and 36 as well as inverting devices 38 and 40, andstandard signal transmitters 42 and 44. Consider that the system is tooperate such that the vehicle illustrated in FIG. 1A is to travel in aleft to right direction, that is, the vehicle is to travel in a forwarddirection, from FIG. 1A to FIG. 1B. A switch 46 in the control device 24is switched to a forward position. A positive DC signal +Vl is providedto the base electrode of the transistor 34 through resistors 48 and 50respectively. The +Vl signal is of sufficient positive magnitude to makethe transistor 34 conductive, whereby the collector electrode of thetransistor 34 is held substantially at ground potential. The ground orvolt potential at the collector electrode of the transistor 34 isapplied to the input terminal of the inverting device 38 and a signal ofpositive potential +V (a binary I level) is provided at the outputterminal of the inverter 38 and this positive potential, which is asignal indicative of forward movement of the vehicle is provided as anenabling signal to various logic elements in FIG. 1. The 0 volt signalenables transmitter 42 to transmit a forward command to the vehicle byway of the input terminal of signal transmitter 44. This positive signalcauses the signal transmitter 44 to become inoperative, and accordinglyno reverse command signal is transmitted to the vehicle.

In reference to FIGS. 1A and 1B, each vehicle control block contains thesame type logical elements. Therefore the operation of vehicle controlblock 2 is to be explained in detail, and it is to be understood thatvehicle control blocks 1 and 3 operate in a similar manner. FIGS. 1A and18 may be placed end to end to more readily envision the systemoperation. Elements in vehicle control block 2 have the letter aappended to their numeral designation, like logical elements in vehicleblock 1 have the letter b appended, and like logical elements in vehicleblock 3 have the letter c appended. Assume initially that there is novehicle present in either vehicle control block 1, vehicle control block2 or vehicle control block 3. All of the bistable devices 58 and 60,therefore, are in a reset state. In vehicle control block 2 as shown inFIG. 1A, the signal receiving apparatus 480 is therefore not sensing thetransmission 7 of either a signal at a frequencyfl from the frontvehicle car 4 of the vehicle 2 or a radio signal transmission atfrequencyj2 from the rear vehicle car 6 of the vehicle 2. The radiofrequency signal receiver 48a may be any of a number of'radio signalfrequency receivers known in the art, and therefore need not bedescribed in detail. The radio receiver 48a senses the radio signaltransmission at frequency f1 through an antenna 50a and senses thetransmission of the radio signal at a frequencyfi through an antenna520. 'In practice the antennas 50a and 52a extend along the roadway forthe length of the vehicle control block 2, that is, the antenthe antenna26. Since the switch 46 is applying positive potential to the baseelectrode of the transistor 34 there is a 0 voltlevel applied to thebase electrode of the transistor 36. The base and emitter electrodes oftransistor 36 therefore are essentially at the same potential, namely 0volts, and the transistor 36, therefore, is nonconductive. The collectorelectrode of transistor 36 is substantially at a potential +V2, astransistor 36 is nonconductive. This positive potential +V2 is appliedto the input terminal of the inverting device 40 and an output signal ofzero volts is produced at the output terminal 32 of the device. Thiszero volt signal (a binary 0 level) is indicative of the vehicle notbeing commanded to travel in the reverse direction,

and-this signal is provided as a disabling signal to various logicelements in FIGS. 1A and 1B. The positive potential +V2 is coupled byway of a capacitor 47 to nas 50a and 52a would essentially extend fromthe dividing line 12 to the dividing line 14. The antennas in vehiclecontrol blocks 1 and 3 would extend along the roadway in like manner, inthe respective vehicle control blocks which they are operative with.

Since the receiver 48a is not sensing radio signal transmissions thereare no signal indications produced on the output lines 54a and 56arespectively, and the storage or bistable devices such as the set andreset flipflops 58a and 60a remain in a reset condition. The one outputterminals of the flip-flops 58a and 60a therefore are at a binary zerolevel and the zero output terminals of the flip-flops are at a binaryone level. The zero output terminals of the flip-flops 58a and 60a arecoupled to the input terminals of an AND gate 62a. This enables the ANDgate 62a to provide a signal at a binary one level to the first inputterminal 64a of an AND gate 66a and also to the first input terminal 68aof an AND gate 70a. The second input terminal 72a of the AND gate 700receives the reverse command signal from the control device 24, andsince the control device 24, as explained above, is set in a forwardrunning condition the signal applied to the second input terminal 72a isat a binary zero level and, therefore, the output signal from the ANDgate 70a also is at a binary zero level. The second input terminal 74aof the AND gate 66 a receives the forward running command signal fromthe control device 24 and this signal is at a binary one level at thistime. Since both input terminals of the AND gate 66a are at a binary onelevel at this time a signal at a binary one level is produced at theoutput terminal of the AND gate 66a and is coupled via line 76b to aspeed encoder 78b in vehicle control block 1. This signal which is at abinary one level, is indicative of there being no vehicle present invehicle control block 2. The speed encoder 78b in vehicle control block1 therefore may generate a speed control signal for vehicles withinvehicle control block 1. Since there is no vehicle present in vehiclecontrol blocks 1 and 3 at this time, gate 66b in logic circuit 33b isproviding a binary 1 signal to the speed encoder in vehicle controlblock 0 (not shown) so that speed encoder may generate a speed commandfor a vehicle in vehicle control block 0. Gate 660 is providing a binary1 signal on line 76a to speed encoder 78a in block 2 and a binary 1signal on line 102b to speed encoder 78b in vehicle control block 1.

Consider now that a vehicle is in control block 1 and is beginning toenter vehicle control block 2. As the front vehicle car 4 passes thedividing line 12 between vehicle block 1 and vehicle block 2 the radiofrequency transmissions from the antenna 18 are received by the antenna50a of the radio frequency receiver 48a and a signal at a binary onelevel is produced on the line 54a setting the flip-flop 58a to thebinary one state. Flipflop 58a now stores a first vehicle presencesignal at this time. Flip-flops 58b and 60b in vehicle control block 1are in a binary l or set state at this time as they are each storing avehicle presence signal, and will continue to do so until the vehicle 2is completely within vehicle control block 2, and completely withoutvehicle control block 1. This is to be made more clear shortly. A signalat a binary one level is produced at the one output terminal of theflip-flop 58a and is coupled to a first input 80a of an AND gate 820 andis also coupled via a line 106a to a differentiating and detectingnetwork 840 and in turn to a first input 86c of an AND gate 88c in logiccircuit 33c of vehicle control block 3 (FIG. 1B). The gate 88c is alsoreceiving a reverse command at this time and is therefore disabled. Thezero output terminal of the flip-flop 58a is now at a binary zero levelwhich in turn causes the AND gate 62a to produce a signal at a binaryzero level at its output, and the output terminal of the AND gate 66a inturn produces a signal at a binary zero level. This binary zero signalwhich is coupled via the line 76b to the speed encoder 78b, informsvehicle control block 1 that vehicle control block 2 is now occupied andthe speed encoder 78b in vehicle control block 1 ceases to transmitcontrol signals to any vehicle entering vehicle control block 1, as itis disabled by the binary 0 signal. Any vehicle'thereafter enteringvehicle control block 1 while there is a signal indicative of a binaryzero level present on the line 76b is given a zero speed command signalwhich causes the vehicle to stop. The vehicle stopping is therefore notpermitted to proceed any further in vehicle block 1 or to enter vehiclecontrol block 2. The vehicle entering vehicle block 1 is not given avehicle speed command signal until both the flip-flops 58a and 60a invehicle control block 2 are concurrently in the reset state, as is to beexplained shortly.

As the vehicle 2 continues from vehicle control block 1 into vehiclecontrol block 2 the rear vehicle car 6 subsequently enters vehiclecontrol block 2, and the receiving antenna 52a of receiver 480 receivesthe radio frequency signal transmissions at frequency f2 from theantenna 22 mounted on the rear vehicle car 6.

A signal at a binary one level is produced on the line 56a and inresponse thereto the flip-flop 60a is set to the binary one state. Thesignal from the one output terminal of flip-flop 60a, which is now atabinary one level is coupled to a first input b of an AND gate 92b byway of a differentiating and detecting network 94b in logic circuit 33bin vehicle control block 1. The differentiating network 94b includes aresistor b, a

capacitor 98b and a diode l00b. The time constant of the differentiatingnetwork is such that in response to the leading edge of the binary onepulse produced at the one output terminal of the flip-flop 60a, apositive pulse is produced by the network 94b which is coupled via thediode l00b to the first input terminal of the AND gate 92b. Since thesecond input terminal of the AND gate 92b is receiving a forward runningsignal, which is also at a binary one level at this time, a binary onesignal is produced at the output terminal of the AND gate 92b and isprovided to a first input terminal of an OR gate 96b. The outputterminal of the OR gate 96b produces a pulse at a binary one level inresponse to the binary one signal at the input terminal and this signalis concurrently applied to the reset terminals of the flip-flops 58b and60b in vehicle control block 1. This signal resets the flip-flops 58band 60b and is indicative of the vehicle which was in vehicle controlblock 1 as now being completely within vehicle control block 2 since theflip-flop 60a in vehicle control block 2 is set to the binary one statein response to the rear vehicle car 6 of the vehicle 2 entering vehiclecontrol block 2.

The differentiating and detection network 94b is needed since theflip-flop 60b in vehicle control block 2 remains in the one state untilit is reset in response to the rear vehicle car 6 of the vehicle 2entering vehicle control block 3. If a vehicle were to now enter vehiclecontrol block 1, the flip-flops 58b and 60b in vehicle control block 1would be successively set to the binary one state. However, if thedifferentiating network 94b were not present the flip-flops 58b and 60bafter being set to the one state would be responsive to the binary onepulse still present at the one output terminal of the flip-flop 60a invehicle control block 2, and so being responsive could be reset to'thebinary zero state which would be an indication that vehicle controlblock 1 were in an unoccupied condition which is not the case.

Since there is no vehicle present in vehicle control block 3 at thistime a signal at a binary 1 level is present on line 76a and speedencoder 780 therefore is permitted to transmit a vehicle speed commandto the vehicle 2 such that the vehicle 2 may continue on its path oftravel through vehicle control block 2, and subsequently into vehiclecontrol block 3.

if there is a failure of radio frequency transmission from the vehicle2, or a failure in the receiver 48a, or if the flip-flop 58a fails tocontinue the storage of the binary 1 vehicle presence signal which isindicative of the front of the vehicle being present in the vehicleblock 2, there must be a means for preventing the generation of avehicle speed command by the speed encoder 78a for transmission to thevehicle 2. This is accomplished by means of the AND gates 82a and 85aand the OR gate 86a. A first input to the AND gate 82a is from theoutput terminal of receiver 48a via the line 87a. A binary one signal ispresent there as long as the receiver 48a is receiving a signal atfrequency fl from the front vehicle car 4,- and the receiver 48a isproducing an output signal. The second input terminal 80a of the ANDgate 82a is connected to the one output terminal of the flip- I flop58a. A binary one signal is produced at this terminal as long as theflip-flop 58a is in the set state, which is indicative of 58a storing avehicle presence signal. The AND gate 82a produces a signal at a binaryone level at its output only so long as there is a binary one signalproduced by the receiver 48a and concurrent therewith the flip-flop 58-is in the binary one state. This binary one signal which is produced atthe output terminal of the AND gate 82a is applied to a first input 89aof the AND gate 85a. 'T he second input signal applied to AND gate 85ais the forward running command from the control device 24, which is at abinary one level at this time. The AND gate 85a therefore produces asignal at a binary one level at its output terminal and this signal isprovided to a first input terminal of the OR gate 86a which in turnproduces a binary one signal at its output terminal. As long as there isa binary one signal produced at the output terminal of the OR gate 86athe speed encoder 78a is permitted to provide a vehicle speed controlsignal, for vehicle control block 2 if there is also provided a binaryone signal on the line 76a from AND gate 66c However, if there is afailure in transmission from the vehicle, or a failure in the receiver48a or a failure of the flip-flop 58a to continue the storage of abinary one signal while the vehicle is present in the vehicle controlblock 2, or there is a failure of a gate 82a, 85a or 86a, a binary zerosignal is provided at the output terminal of the OR gate 86a to thespeed encoder 78a and a zero speed command signal is transmitted to thevehicle, stoppingthe vehicle in vehicle control block 2.

As the vehicle 2 enters vehicle control block 3 (as shown in FIG. 1B)the receiver 480 begins to receive the radio frequency transmission atfrequencyfl and the flip-flop 580 in turn is set to the binary onestate, storing a vehicle presence signal. A signal at a binary zerolevel is produced at the zero output terminal of the flip-flop 58C whichdisables the AND gate 620 and in turn disables the AND gate 66cproducing a signal at a binary zero level on the .line 76awhich'prevents the speed encoder 78a in vehicle control block 2 fromgenerating vehicle speed commands. The momentum of the vehicle 2 issufficient to permit it to continue into block 3 a distance far enoughfor it to begin to receive vehicle speed commands from the speed encoder780 in vehicle control block 3. The flip-flops 58a and 60a in vehiclecontrol block 2 are still in the set state which is a block occupiedcondition for vehicle control block 2. These last-named flip-flopsremain in the set state until the rear vehicle car 6 of the vehicle 2 isentered into vehicle control block 3.

Consider now that the rear vehicle car 6 of vehicle 2 is now enteringvehicle control block 3. Radio signal receiver 48c receives the radiofrequency signal transmission at frequency f2 and in response thereto abinary one signal is produced on the line 56c setting the flip-flop 600to the binary one state. The binary one signal produced at the oneoutput terminal of flipflop 600 is coupled to the differentiatingnetwork 94a in vehicle control block 2 (as shown in FIG. 1A) and in turnto the firstinput terminal of the AND gate 92a.

The second input terminal of the AND gate 92a is receiving the forwardrunning control signal from control device 24, which is at a binary onelevel at this time. The AND.gate 92a therefore produces a binary onesignal at its output terminal which is coupled to the first inputterminal of the OR gate 96a which in turn produces a binary one signalat its output and in turn the binary one signal at the output terminalof the OR gate 960 resets the flip-flops 5811 and 60a to the binary zerostate, so they are no longer storing vehicle presence signals. Theresetting of these flip-flops is indicative that the vehicle 2 has leftvehicle control block 2 and is now in vehicle control block 3. As wasexplained earlier there is also a binary zero level present on the line76a which is indicative of at least the front vehicle car 4 of thevehicle 2 being present in vehicle control block 3. The speed encoder78a in vehicle control block 2 therefore is prevented from transmittinga vehicle speed command to any vehicle which is entering vehicle controlblock 2- at this time. This is a safety measure which prevents asucceeding vehicle which is entering the vehicle control block 2 fromcontinuing from vehicle control block 2 into vehicle control block 3 andthereby colliding with the vehicle 2 which is now in vehicle controlblock 3.

' There may be more than one input to the speed encoder 78a than fromthe preceding vehicle control block. If the effective braking distanceof the vehicle is one vehicle control block in length there need be onlya control signal provided from the succeeding vehicle control block tothe speed encoder. If, however, the vehicle has an effective'brakingdistance oftwo vehicle control blocks in length a control signal wouldbe coupled to the speed encoder from the two succeeding vehicle controlblocks. For example, the speed encoder in vehicle control block 1 wouldreceive control signals via the line 76b from vehicle control block 2and would also receive a control signal from vehicle control block 3 viathe line l02b, if the effective braking distance of the vehicle is twovehicle control blocks in length, and the vehicle is traveling in theforward direction. The operation of the system repeats itself as thevehicle 2 travels through succeeding vehicle control blocks.

Consider now the operation of the system when the vehicle 2 is given areverse running control signal from the control device 24 (as shown inFIG. 1B). First assume that all vehicle control blocks are empty andtherefore the flip-flops 58 and 60 in each of the vehicle control blocksare in the reset state at this time. Now consider that the vehicle 2 isrunning in the reverse direction from vehicle control block 3 and isentering vehicle control block 2. The flip-flops 58c and 60c (vehiclecontrol block 3, FIG. 18) would be in a set state at this time. Theradio frequency receiver 48a begins to receive radio signals atfrequency/2 from the rear vehicle car 6 of the vehicle 2 as it entersvehicle control block 2. In response to the radio frequency signals atfrequencyfi the receiver 48a produces a binary one signal one the line56a setting the flip-flop 60a to the binary one state. The flip-flop 60anow stores a vehicle presence signal. The binary one signal produced atthe one output terminal of the flip-flop 60a is coupled to the firstinput terminal of the AND gate 92b in vehicle control block 1 by way ofdifferentiating network 94b. However, the forward running control signalis at a binary zero level at this time and the output of the AND gate 92therefore is at a binary zero level at this time and theflip-flops 58band 60b do not receive a reset signal by this circuit at this time.Since the flip-flop 60a is in the binary one state at this time, asignal at a binary zero level is produced at the zero output terminal ofthe flip-flop 60a. This zero binary signal is coupled to the secondinput of the AND gate 62a disabling this gate and in turn disabling ANDgate 700 which is receiving a binary one reverse running control signalat its other input terminal. This binary zero signal at the outputterminal of the AND gate 70a is coupled .continuing through vehicleblock 3 and colliding with thevehicle 2 in vehicle control block 2.

As the vehicle 2 continues into vehicle control block 2 the frontvehicle car 4 subsequently enters vehicle' control block 2 and thereceiver 48a begins to receive the radio frequency transmission atfrequencyfl and in turn produces a binary one signal on the 'line 54athereby setting the flip-flop 58a to the binary one state. This in turnproduces a binary one signal at the one output terminal of the flip-flop58a. The flip-flop 58a now stores a vehicle presence signal. The vehicle2 is now completely within the vehicle control block 2 and the binaryone signal present at the one output terminal of the flip-flop 58a iscoupled via a line 106a through differentiating and detecting network84c, (as shown in FIG. 18) to a first input terminal of the AND gate88c, in vehicle control block 3. The second input terminal of the ANDgate 88c is receiving a binary one signal as the reverse running commandfrom the control device 24 is at a binary one level at this time. Abinary one signal is produced at the output terminal of the AND gate 88cand is coupled through the OR gate 960 to the reset terminals offlip-flops 58c and 60c resetting these flipflops. The flip-flops 58c and600 are now no longer storing vehicle presence signals. The binary onesignals produced at the zero output terminals of the flip-flops 58c and60c are coupled to the inputs of the AND gate 620 producing a binary onepulse at the output terminal of the AND gate 620. This binary one signalis coupled to the first input terminal of the AND gate 70C. The

other input terminal of the AND gate 70c is receiving the binary onereverse running control signal and the AND gate produces a binary onesignal at its output terminal which is provided to the speed encoder 780in vehicle control block 4 (not shown) by way ofline 112C for providinga control signal such that the speed encoder 78 in vehicle control block4 may generate speed control signals for vehicles in or entering vehiclecontrol block 4.

As was the case when the vehicle was running in the forward directionthere must also be a means when the vehicle is traveling in the reversedirection for detecting when the receiver 48a no longer senses atransmission at radio frequency f2, or senses when there is a failure inthe receiver 48a, or when the flip-flop 60a no longer stores a vehiclepresence signal when the vehicle 2 is still within the vehicle controlblock 2. The AND gate 108a and the AND gate 110a perform the samefunctions as the AND gates 82a and a, respectively, did when the vehiclewas traveling in the forward direction. The first input signal to theAND gate 108a is the binary one pulse produced on the line 560 fromreceiver 48a. The second input to the AND gate 108a is from the oneoutput terminal of the flip-flop 600. As long as there is a binary onesignal produced on the output line 56a and the flip-flop 60a remains inthe set state, a binary one signal is produced at the output terminal ofthe AND gate 1080. This signal is coupled to a first input of the ANDgate a. The second input to the AND gate 1 10a is the reverse runningcontrol signal which is at a binary one level at this time. In responseto these two signals, which are concurrently at a binary one level, abinary one signal is produced at the output terminal of the AND gate110a and is coupled via the OR gate 86a to the speed encoder 78ainforming the speed encoder 780 that it may continue to generate vehiclespeed control signals for the vehicle 2 in vehicle control block 2. Inthe event there is a failure in transmission or reception of the radiofrequency signal f2 while the vehicle is in vehicle control block 2 orthe flip-flop 60a no longer stores a vehicle presence signal, or thereis a failure of one of the gates 108a, 110a or 86a, a binary zero signalis produced at the output terminal of the OR gate 86a and the speedencoder 78a is prevented from generating vehicle speed control signalsfor the vehicle 2 while it is in vehicle control block 2.

As the vehicle 2 first enters vehicle control block 1 from vehiclecontrol block 2 the receiver 48b in vehicle control block 1 begins toreceive the radio frequency transmissions at frequency f2. A binary onesignal isv produced on the output line 56b in response thereto settingthe flip-flop 60b to the binary one state, thereby storing a vehiclepresence signal. Since the flip-flop 60b is now in the binary one state,a binary zero signal is produced at the zero output terminal of theflip-flop 60b, The AND gates 62b and 70b therefore are disabled and asignal at a binary zero level is produced at the output terminal of theAND gate 70b which in turn is provided to the speed encoder 78a invehicle control block 2 causing the speed encoder 78a to no longergenerate vehicle speed control signals for any vehicle entering vehiclecontrol block 2, thereby preventing a vehicle from entering vehiclecontrol block 1 from vehicle control block 2 as long as the vehicle 2 isin vehicle control block 1. As the front vehicle car 4 of vehicle 2enters vehicle control block 1, receiver 48b begins to receive the radiofrequency transmissions at frequencyfl and a binary one signal isproduced on the line 54b and flip-flop 58b is set to the binary onestate in response thereto, thereby storing a vehicle presence signal.The resulting binary one signal produced at the one output terminal ofthe flip-flop 58b is provided via differentiating and detecting circuit84a to a first input terminal of AND gate 880 in vehicle control block2. The second input terminal of the AND gate 88a receives the reverserunning control signal which is at a binary one level at this time. As aresult, a binary one signal is produced at the output terminal of theAND gate 88b and is coupled via OR gate 96a to the reset terminals ofthe flip-flops 58a and 60a concurrently resetting these flip-flops. Theresulting binary one signals produced at the zero output terminals ofthe flip-flops 58a and 60a are coupled to the first and second inputterminals, respectively, of the AND gates 62a producing a binary onesignal at the output terminal, of the AND gate 62a. This binary onesignal is coupled to a first input terminal of the AND gate 70a and thesecond input terminal of the AND gate 70a is receiving a reverse runningcontrol signal which is at a binary one level at this time. Theresultant binary one signal at the output terminal of the AND gate 70ais coupled via a line 110a to speed encoder 780 (vehicle control block3, FIG. 1B). This binary one signal permits the speed encoder 780 toprovide vehicle speed control signals for any vehicle in or enteringvehicle control block 3, as vehicle control block 2 is now absent avehicle. As the vehicle 2 proceeds in the reverse running direction fromvehicle control block 1 into vehicle control block (not shown) theoperation of the vehicle control and detection system repeats itself.

In reference to FIG. 2 there is shown a block diagram of a vehiclecontrol and detection system for forward running of a vehicle utilizingrelays rather than solid vehicle control block 1 is entered in vehiclecontrol state logic devices. The vehicle 2 is identical to the vehicle 2illustrated in FIG. 1A of the drawings as are the radio frequency signalreceivers 48 and the speed encoders 78, illustrated in FIGS. 1A and 1B.The control device 150 shown in the lower portion of FIG. 2 performs thesame function as the control device 24 in FIG. 1, that is, it informsthe vehicle as to whether or not it is to travel in a forward or reversedirection and it applies reset signals to the terminals 152 of therelays and control signals to the terminals 154 of the relays when thevehicle is to travel in the forward direction. FIG. 3 of the drawings isexplained in detail subsequently for the reverse running operation ofthe vehicle.

Assume that the vehicle 2 is completely within vehicle control block 2and is traveling from left to right, the forward direction, asillustrated in FIG. 2. The relays in each of the vehicle control blocksillustrated have their relay contacts in the positions as illustrated,that is the relays in vehicle control block 2 are energized, and therelays in vehicle control blocks 1 and 3 are deenergized. The radiofrequency receiver 480 is receiving a radio frequency signal atfrequencyfl from the front vehicle car 4 and is receiving a radiofrequency signal at frequency f2 from the rear vehicle car 6. A signalis applied, therefor, via the line 1150 to the coil of a relay 114aenergizing the, relay. The relays contacts 126a therefore assume theclosed position shown. The relay 114a is a standard type relay thatremains energized only so long as an energizing signal is applied to itsinput. The relay 1160 is the same type relay as the relay l14a and it isenergized by an energizing signal applied via the line 117a in responseto the radio frequency signal at frequency [2, being sensed by receiver48a. The coil of relay 114a is connected in series with the set coil 118a of a bistable or biased relay 1190. Once the set coil 118a receives anenergizing signal the relay contacts 130a and 132a assume the positionsshown and remain in the positions shown after the energizing signal isremoved. The positions of the contacts of the bistable relay 119a do notchange until the reset coil l20a'of the bistable relay 119a receives areset energizing signal. When the set coil 1 18a becomes energized andthe relay contacts assume thepositions as shown the relay 119a isstoring a vehicle presence signal, that is, the relay 1 19a being in the5 set state is indicative of the front vehicle car 4 of the trainvehicle 2 being present in vehicle control block 2. The set coil 12212of the bistable relay 121a is connected in series with the coil of therelay 116a. The bistable relay 121a is the same type as the relay 119a.The energizing signal applied to the set coil 122a energizes the relayand the relay contacts 134a, 136a and 138a assume the positions shown.The energization of the set coil 122a is indicative of the storing of avehicle presence signal which is indicative of the rear vehicle car 6 ofthe train vehicle 2 being present in vehicle control block 2. Thepositions of the contacts of bistable ,relay 121a remain in a position,as shown, until the reset coil 124a receives a reset signal.

6 Since the train vehicle 2 is situated within the vehicle control block2 it is necessary that the speed encoder 78b in vehicle control block 1not be permitted to transmit a vehicle speed control signal to a vehiclein or entering vehicle control block 1. The control signal for block 2at the terminal 154a, and the signal is transmitted through the contacts138a of bistable relay 12111 which contacts are now open and through thecontacts 132a of bistable relny ll9a, which contacts also are open.Therefore, the control signal path for the en coder 78b is open.Continue the tracing of control signal path from vehicle control block 2to vehicle control block 1. The relays 11612 and 121b in vehicle controlblock 1 are each deenergized, as shown, since there is not a vehicle invehicle control block 1. Therefore, following the control signal fromvehicle block ,2 it travels from the contacts 132a of the relay 119a tothe contacts 136 b of the relay l21b and through the contacts l28b ofthe relay 1l6b to the speed encoder 78b. Though the last two mentionedsets of relay contacts are open as shown it is readily seen that even ifa vehicle were completely within vehicle control block 1 and the relayll6b were energized and the set coil 122b had been energized and wasthereby set such that the relay contacts 12817 of the relay 1l6b and therelay contacts 136b of the relay 12lb were closed there would still notbe a complete circuit path for the control signal as the bistable relays119a and 121a in vehicle control block 2 are each in the set conditionthereby blocking the control signals path from vehicle control block 2to vehicle control block 1.

However, with the vehicle 2 being completely within the vehicle controlblock 2, vehicle control block 1 must be informed that the vehicle 2 isnow completely without vehicle control block 1 and is completely withinvehicle control block 2. The reset signal for vehicle control block 1 isapplied from the control device 150 to the terminal 152a of the bistablerelay 121a. The signal is transmitted through the closed relay enteringvehicle control block 1. The bistable relays 119k and l21b are shown inthe reset state at this time. As vehicle 2 continues its travel throughvehicle control block 2 and then begins to enter vehicle control block-3, the radio frequency receiver 48a in vehicle control lock 2 no longersenses the radio frequency transmissions at frequency fl and relay 114atherefore becomes deenergized. Bistable relay 119a, however, remains inthe set state until receiving a reset signal from vehicle control block3 when the vehicle 2 is completely within vehicle control block 3. Radiofrequency receiver 480 in vehicle control block 3 now begins to receiveradio frequency transmissions at a frequencyfl from the from vehicle car4 of the vehicle 2 and applies an energizing signal. via the line 1150to the coil of the relay 1140 energizing this relay. The contacts 1260therefore assume a closed position. The control signal from vehiclecontrol block 2 for reverse running of a vehicle within vehicle controlblock 3 is applied to these contacts of the relay for application to thespeed encoder 780. Thefunction of this signal is explained in regard toreverse running operation for FIG. 4. At this time there is no signalapplied to the contacts 1260 of this relay as the vehicle is running inthe forward direction. The energizing signal is also applied to the setcoil 1180 of the bistable relay 1190 thereby setting the bistable relay.The bistable relay 1 190 is now storing a first vehicle presence signalthat is indicative of the first vehicle car 4 of the vehicle 2 beingpresent within vehicle control block 3, and the bistable relay 1190remains in the set state until being reset by a reset signal fromvehicle control block 4 (not shown) when the vehicle 2 is completelywithout vehicle block 3 and is completely within vehicle control block4. The relay contacts 1300 now switch to a'closed position and the relaycontacts 1320 switch to an open position. The opening of the relaycontacts 1320 of the bistable relay 1190 in vehicle control block 3interrupts the application of the control signal for vehicle block 2which is applied to the terminal 1540 of the relay 1210. Therefore, thespeed encoder 78a no longer receives a control signal and therefore nolonger may generate a vehicle speed control signal for a vehicleentering vehicle block 2 as there is now a vehicle in vehicle controlblock 3. The closed contacts 1300 of relay 1190 form part of the pathfor the application of the reset signal to the reset coils 120a and 124aof the bistable relays 119a and 121a, respectively, in vehicle controlblock 2. The complete-path for the reset signal is not closed howeveruntil the set coil 1220 of relay 1210 is energized when the secondvehicle car 6 of vehicle 2 enters vehicle control block 3. As the secondvehicle car 6 of the vehicle 2 enters vehicle control block 3, radiofrequency receiver 480 begins to receive radio frequency transmissionsat frequency f2 and applies an energizing signal via the line 1170 tothe coil of the relay 1160 energizing the relay and closing the contacts1280. The energizing signal is also applied to the set coil 1220 of thebistable relay 1210, setting the bistable relay which now stores asecond vehicle presence signal, which is indicative of the secondvehicle car being present in vehicle control block 3. Relay contacts1340 and 1360 now assume a closed position and relay contacts 1380assume an opened position. Since contacts 1360 of relay 1210 are closedat this time as are contacts 1280 of the relay 1160 there is a path forthe control signal to be applied to the speed encoder 78c from vehiclecontrol block 4 (not shown) such that the speed encoder 780 may transmitvehicle speed control signals to the vehicle 2. The closing of the relaycontacts 1340 of the relay 1210 now provide a complete circuit path forthe reset signal which is applied to terminal 1520 of the relay 1200 toreset .the bistable relays 119a and 124a in vehicle control block 2. Thereset signal is applied to the terminal 1520then through the closedrelay contacts 1340 of bistable relay l2lcthrough the closed relaycontacts 1300 of the bistable relay 1190 in vehicle control block 3, andfrom there to the reset coils 120a and 124a of the bistable relays 119aand 121a respectively, in vehicle control block 2. This informs vehiclecontrol block 2 that the vehicle 2 is now completely within vehiclecontrol block 3 and vehicle control block 2 is now in condition topermit another vehicle to enter. The travel of the vehicle 2 tosucceeding blocks is accomplished in a similar manner to that which wasexplained above.

The relay embodiment of the invention shown has the same safety featureas the logic embodiment shown in FIGS. 1A and 18 that feature being thatif the vehicle is within a given vehicle control block and there is afailure in transmission of the radio frequency signals to the receiver48 or the receiver 48 in a given vehicle control block has some type offailure whereby it does not provide an energizing signal for the relays,or if there is some relay failure, the speed encoder is prevented fromgenerating a vehicle control signal. This may readily be seen byreferring to vehicle control block 2 and assuming that the vehicle 2 iswithin the vehicle control block as shown. The relay contacts thereforealso will be in the positions as shown. The control signal which isapplied to the speed encoder 78a is applied through the closed contacts1360 of the bistable relay 121a and the closed contacts 128a of therelay 116a. As was earlier mentioned the relay 116a remains energizedand the contacts 128a therefore remain closed only so long as anenergizing signal is applied to the relay 116a. It is seen thereforethat if there is a failure in transmission of the radio frequency signalfrom the vehicle 2 or if there is a failure in the radio frequencyreceiver 48a or if the relay 1 16a itself fails, it follows that therelay 116a becomes deenergized, the contacts 128a open and the controlsignal is no longer applied to the speed encoder 78a and there aretherefore no vehicle speed control signals generated. Although thebistable relay 121a remains in the set condition after an energizingsignal is initially applied to the set coil, in the event that the relayfails in some manner and no longer stores a signal indicative of thevehicle being present in the vehicle control block 2 when the vehicle isin fact present in vehicle control block 2, the relay contacts 136awould be opened and again the path for the control signal to the speedencoder 78a would be opened and no vehicle speed control signals couldbe generated.

In reference to FIG. 3 there is shown the embodiment for the vehiclecontrol and detection system utilizing relays, for reverse running ofthe vehicle 2. The relays are the identical relays as shown in FIG. 3 asis the control device 150, the only difference being that in FIG. 4 therelay contacts for reverse running are shown, and the contacts forforward running are not shown. The terminals 156 to which reset signalsare applied for reverse running conditions from the control device 150and the terminals 158 to which the control signals are applied forreverse running are shown, but the terminals 152 and 154 for forwardrunning are not shown. If the vehicle is to travel in the reversedirection the control device 150 applies the reset and control signalsto the terminals 156 and 158, respectively, and transmits a reversedirection of travel control signal to the vehicle.

Assume that the vehicle 2 is within the vehicle control block 2 as shownand is traveling in a reverse direction that is from right to left, asis illustrated by the arrow on the drawing. Since the vehicle 2 iscompletely within vehicle control block 2 as shown, the radio frequencyreceiver 48a is receiving radio frequency transmissions at bothfrequenciesfl andj2 and energizing signals are applied via the lines115a and 117a to the relays 114a and 1 160, respectively, energizingthese relays, and in turn closing the contacts 126a and 128a,respectively, as shown. The set coils 118a and 122a of the bistablerelays 119a and 121a, respectively, in turn receive the energizingsignals and are set, thereby storing first and second vehicle presencesignals, respectively, which are indicative of the vehicle 2 beingcompletely within vehicle control block 2. Since vehicle control block 1is absent a vehicle, as shown, the control signal for vehicle controlblock 2 which is applied to the speed encoder 78 a is first applied tothe terminal 158b of bistable relay ll9b which is in the reset conditionat this time through the closed contacts 14212 of bistable relay 11912and through the closed contacts 1481) of the bistable relay 121b, whichis in the reset condition at this time, and through the closed contacts140a of bistable relay 119a which is in the set condition at this time,and through the closed contacts 126a of the energized relay 114a, and inturn to the speed encoder 78a. The speed encoder 78a then transmitsvehicle speed control signals to the vehicle 2. The relay 116a hasapplied to its closed contacts 1280 control signals from block 3 forforward running, there is however at this time no signal applied tothese contacts as the control device 150 is only sending out signals forthe reverse running condition.

Since the vehicle 2 is completely within vehicle control block 2, it iswithout vehicle control block 3 and the relays in vehicle control block3 may be reset, as shown in the drawing. The reset signal for thebistable relays in vehicle control block 3 is applied to the terminal156a of the bistable relay 119a. From there the signal is coupledthrough the closed contacts 144a of bistable relay 119a, through theclosed contacts 146a of the bistable relay 121a which is now in the setcondition and from there to the reset coils 1200 and 1240 of thebistable relays 119C and 121C, respectively. The bistable relays invehicle control block 3 are now in a condition to be once again set andto sense the presence ofa vehicle in vehicle control block 3.

The relay 114a as well as the relay 119a achieve the failsafe feature ofinterruption of the control signal to the speed encoder 78a forpreventing the generation of a vehicle speed control signal in the eventthatthe receiver 48a no longer senses the presence of the vehicle 2 whenit is within vehicle control block 2, or if the relays 1140 or 119a failin such a manner that a vehicle presence signal is no longer stored, aswas explained for the forward running condition as illustrated in FIG.3.

As the rear vehicle car 6, which is the first vehicle car of vehicle 2to enter vehicle control block 1 does so, radio frequency receiver 480in vehicle control block 2 no longer receives radio frequencytransmissions at frequency /2 and the relay 116a in vehicle controlblock 2 therefore becomes deenergized. At substantially the same timeradio frequency receiver 48b in vehicle control block 1 senses the radiofrequency transmissions at frequency f2 and an energizing signal isapplied via the line 1 17b to the relay l16b energizing the relay. Theenergizing signal in turn is applied to the set coil 122b of thebistable relay 121b setting the relay and thereby storing a firstvehicle presence signal. The I relay contacts 146b close and the relaycontacts 1481) of the relay l2lb open. The opening of the relay contacts148b opens the path for the control signal which is applied from theterminal 158b in vehicle control block 1 to the speed encoder 78a invehicle control block 2 thereby preventing the generation of vehiclespeed control signals in vehicle control block 2. The closing of thecontacts 14Gb of the relay l2lb is the first step in the closing of apath for a reset signal to be applied to the reset coils a and 124a ofthe bistable relays 119a and 121a in vehicle control block 2 as shall beexplained shortly.

As the front vehicle car 4 enters vehicle control block 1 the radiofrequency receiver 48a in vehicle control block 2 no longer senses thetransmission of radio frequency signals at frequencyfl and the relay1140 in vehicle control block 2 becomes deenergized opening the relaycontacts 126a. At substantially the same time radio frequency receiver48b in vehicle control block 1 begins to receive the radio frequencytransmissions at radio frequency fl and applies an energizing signal torelay ll4b by way of line l15b energizing the relay, closing relaycontacts 126b. The energizing signal is also applied to the set coilll8b of the bistable relay ll9b setting the relay and thereby storing asecond vehicle presence signal which is indicative of the front vehiclecar 4 being present in vehicle control block 1. The relay contacts l42bof bistable relay ll9b open thereby blocking the flow of the controlsignal to vehicle control block 2 and the relay contacts l40b and 144bof the same relay close. The closure of the relay contacts 14Gb providesa path for the control signal from the vehicle control block 0 (notshown) through the closed contacts l40b of relay ll9b through the closedcontacts 126b of the relay 11417 and in turn to the speed encoder 78b sothat vehicle speed control signals may be generated for the vehicle 2which is now completely within vehicle control block 1. The closure ofthe contacts 144b provides a path for the reset signal for the bistablerelays in vehicle control block 2. The reset signal is applied to theterminal 156b of the relay ll9b through the closed contacts l44b of thebistable ll9b relay through the closed contacts 14Gb of the bistablerelay 121b, which is also in the set state, and to the reset coils 120aand 124a of the bistable relays 119a and 121a, respectively, in vehiclecontrol block 2. The relays 1 19a and 1210 in vehicle control block 2are i now in a condition to'be once again set and to store vehiclepresence signals indicative of a vehicle being in vehicle control block2. The system for reverse running operates in a like manner as thevehicle continues fromthe vehicle control block 1 to vehicle controlblock (not shown) and so on.

The showing of separate diagrams for forward and reverse running asshown in FIGS. 3 and 4, respectively, was done to simplify the drawingsand it should be readily apparent to one skilled in the art how onecomposite relay configuration may be laid out as the same relays areused for each running conditions, the only difference being theindividual contacts of the relays which are utilized and which are shownin the respective drawings.

in summary, a vehicle control and detection system has been describeduses either solid state logic devices or relay devices. In response to afirst device sensing the presence of a vehicle within a given vehiclecontrol block a vehicle presence signal is stored and a vehicle speedcontrol signal is generated for the vehicle within the given vehiclecontrol block. In response to the first device no longer sensing thepresence of the vehicle or the I vehicle no longer storing the vehiclepresence signal when the vehicle is within the given vehicle controlblock, or a vehicle is sensed in the succeeding vehicle control block,the vehicle speed control signal for the vehicle in the given vehiclecontrol block is interrupted.

I claim:

1. In a vehicle control system wherein a vehicle travels along a vehicletravel path divided into a plurality of vehicle control blocks, and saidvehicles movement through a given vehicle control block in controlled bya provided vehicle control signal, the combination comprising:

first means for continuously sensing the presence of said vehicle withinsaid given vehicle control block;

second means for storing a vehicle presence signal in response to saidfirst means sensing the presence of said vehicle;

third means for providing said vehicle control signal for said vehiclewithin said given vehicle control block in response to the sensing ofthe absence of another vehicle in at least the vehicle control blocksucceeding said given vehicle control block; and

means responsive to either one of said first means no longer sensing thepresence of said vehicle within said given vehicle control block or saidsecond means no longer storing said vehicle presence signal, during thetime said vehicle is within said given vehicle control block, forinhibiting the provision of said vehicle control signal for said vehiclewithin said given vehicle control block.

2. In a vehicle control system wherein a vehicle includes at least firstand second vehicle cars, and said vehicle travels along a vehicle travelpath divided into a plurality of vehicle control blocks, and saidvehicles movement through a given vehicle control block is controlled bya provided vehicle control signal, the combination comprising:

first means for continuously sensing the presence of said first andsecond vehicle cars within said given vehicle control block;

second means for storing a first vehicle car presence signal in responseto said first means sensing the presence of said first vehicle carwithin said given vehicle control block; i

third means for storing a second vehicle car presence signal in responseto said first means sensing the presence of said second vehicle carwithin said given vehicle control block;

fourth means for providing said vehicle control signal for said vehiclewithin said given vehicle control block in response to the sensing ofthe absence of another vehicle in at least the vehicle control blocksucceeding said given vehicle control block; and

means responsive to any one of said first means no longer (a) sensingthe presence of said first vehicle car or (b) said second vehicle carwithin said given vehicle control block, or (c) said second means nolonger storing said first vehicle car presence signal or (d) said thirdmeans no longer storing said second vehicle car presence signal, duringthe time said vehicle is within said given vehicle control block, forinhibiting the provision of said vehicle 7 control signal for saidvehicle within said given vehicle control block.

3. The combination claimed in claim 2 wherein said first vehicle cartransmits a signal at a frequency fl and said second vehicle cartransmits a signal at a frequency f2, which is different than saidfrequencyfl; and a said second means stores said first vehicle carpresence signal in response to said first means sensing the transmissionof said signal at said frequency f1, and said third means stores saidsecond vehicle car presence signal in response to said first meanssensing the transmission of said signal at said frequencyf2. 4. In avehicle control system wherein a vehicle travels along a vehicle travelpath divided into a plurality of vehicle control blocks, the combinationcomprising: I

first means for continuously sensing the presence of said vehicle withina first vehicle control block;

second means for storing a first vehicle presence signal in response tosaid sensing by said first means;

third means in a second vehicle control block for continuously sensingthe presence of a vehicle within said second vehicle control block;fourth means located in said second vehicle control block and responsiveto said sensing by said third means for providing a second vehiclepresence signal, and said second means discontinuing the storage of saidfirst vehicle presence signal in response to the provision of saidsecond vehicle presence signal;

fifth means for providing a vehicle control signal for another vehiclein a third vehicle control block in response to said second means nolonger storing said first vehicle presence signal; sixth means forproviding a vehicle control signal for said vehicle within said firstvehicle control block in response to said fourth means no longerproviding said second vehicle presence signal; and

means for inhibiting the provision of said vehicle control signal forsaid vehicle within said first vehicle control block in response toeither one of said first means no longer sensing the presence of saidvehicle within said first vehicle control block or said second means nolonger storing saidfirst vehicle presence signal during the time saidvehicle is within said first vehicle control block.

5. The combination claimed in claim 4 wherein said second meanscomprises a first bistable element which is set to a first bistablestate in response to said sensing by said first means, and which remainsin said first bistable state until being set to a second bistable statein response to the sensing of the presence of said vehicle within athird vehicle control block.

6. The combination claimed in claim 5 wherein said 1 fourth meansincludes a second bistable element which is set to a first bistablestate in response to said sensing by said fourth means and which remainsin said first bistable state until being set to a second bistable statein response to the sensing of the presence of said vehicle within athird vehicle control block.

7. In a vehicle control system wherein a vehicle includes at least firstand second vehicle cars, and said vehicle travels along a vehicle travelpath divided into a plurality of vehicle control blocks, the combinationcomprising:

first means for continuously sensing the presence of said first andsecond vehicle cars within a first vehicle control block;

second means for storing a first vehicle car presence signal in responseto said first means sensing the presence of said first vehicle carwithin said first vehicle control block;

third means for storing a second vehicle car presence signal in responseto said first means sensing the presence of said second vehicle carwithin said first vehicle control block; fourth means in a secondvehicle control block for sensing the presence of said first and secondvehicle cars within said second vehicle control block;

fifth means located in said vehicle control block and responsive to saidfourth means no longer sensing the presence of said first and secondvehicle cars for providing a control signal for said first vehiclecontrol block;

sixth means located in said first vehicle control block for generating avehicle control signal for a vehicle within said first vehicle controlblock in response to said fifth means providing said control signal forsaid first vehicle control block; and

means for preventing the generation of said vehicle control signal forvehicles within said first vehicle control block in response to any oneof (a) said first means no longer sensing the presence of said first andsecond vehicle cars within said first vehicle control block or (b) saidsecond means no longer storing said first vehicle car presence signal or(c) said third means no longer storing said second vehicle car presencesignal, during the time said vehicle is within said first vehiclecontrol blockv 8. The combination claimed in claim 7 wherein said firstvehicle car transmits a signalat a frequencyfl and said second vehiclecar transmits a signal at a frequency /2 which is different thanfl; and

said second means stores said first vehicle. car presence signal inresponse to said first means sensing the transmission of said signal atfrequency fl and said third means stores said second vehicle carpresence signal in response to said first means sensing the transmissionof said signal at frequency 9. A method of controlling the movement of avehicle along a vehicle travel path divided into a plurality of vehiclecontrol blocks, wherein said vehicles movement through a given vehiclecontrol block is'controlled by a provided vehicle control signal, saidmethod comprising the steps of:

continuously sensing the presence of said vehicle within said givenvehicle control block; storing a vehicle presence signal in response tosaid sensing the presence of said vehicle within said given vehiclecontrol block; providing said vehicle control signal in response tosensing the absence of a vehicle in at least the vehicle control blocksucceeding said given vehicle control block; and preventing theprovision of said vehicle control signal in response to either one of nolonger sensing the presence of said vehicle in said given vehiclecontrol block or not storing said vehicle presence signal duringt'he'time said vehicle is within said given vehicle control block. 10. Amethod of controlling the movement of a vehicle along a vehicle travelpath divided into a plurality of vehicle control blocks, and saidvehicle includes at least first and second vehicle cars, with saidvehicles movement through a given vehicle control block being controlledby a provided vehicle control signal, said method comprising the stepsof:

continuously sensing the presence of said first and second vehicle carswithin said given vehicle control block; storing first and secondvehicle car presence signals in response to said sensing the presence ofsaid first and second vehicle cars, respectively, within said givenvehicle control block; providing said vehicle control signal in responseto sensing the absence of a vehicle in the succeeding vehicle controlblock concurrent with continuously sensing the presence of said firstand second vehicle carswithin said given vehicle control block duringthe time the first and second vehicle cars presence signals are stored;discontinuing the storage of said first and second vehicle car presencesignals in response to sensing the presence of said first and secondvehicle cars, respectively in said succeeding vehicle control block;providing a vehicle control block unoccupied signal to the precedingvehicle control block in response to the discontinuance of the storageof said first and second vehicle car presence signals; and preventingthe generation of said vehicle control signal for said given vehiclecontrol block in response to either one of no longer sensing thepresence of said first and second vehicle cars within said given vehiclecontrol block or not storing said first and second vehicle car presencesignals during the time said vehicle is within said given vehiclecontrol block.

1. In a vehicle control system wherein a vehicle travels along a vehicletravel path divided into a plurality of vehicle control blocks, and saidvehicle''s movement through a given vehicle control block in controlledby a provided vehicle control signal, the combination comprising: firstmeans for continuously sensing the presence of said vehicle within saidgiven vehicle control block; second means for storing a vehicle presencesignal in response to said first means sensing the presence of saidvehicle; third means for providing said vehicle control signal for saidvehicle within said given vehicle control block in response to thesensing of the absence of another vehicle in at least the vehiclecontrol block succeeding said given vehicle control block; and meansresponsive to either one of said first means no longer sensing thepresence of said vehicle within said given vehicle control block or saidsecond means no longer storing said vehicle presence signal, during thetime said vehicle is within said given vehicle control block, forinhibiting the provision of said vehicle control signal for said vehiclewithin said given vehicle control block.
 2. In a vehicle control systemwherein a vehicle includes at least first and second vehicle cars, andsaid vehicle travels along a vehicle travel path divided into aplurality of vehicle control blocks, and said vehicles movement througha given vehicle control block is controlled by a provided vehiclecontrol signal, the combination comprising: first means for continuouslysensing the presence of said first and second vehicle cars within saidgiven vehicle control block; second means for storing a first vehiclecar presence signal in response to said first means sensing the presenceof said first vehicle car within said gIven vehicle control block; thirdmeans for storing a second vehicle car presence signal in response tosaid first means sensing the presence of said second vehicle car withinsaid given vehicle control block; fourth means for providing saidvehicle control signal for said vehicle within said given vehiclecontrol block in response to the sensing of the absence of anothervehicle in at least the vehicle control block succeeding said givenvehicle control block; and means responsive to any one of said firstmeans no longer (a) sensing the presence of said first vehicle car or(b) said second vehicle car within said given vehicle control block, or(c) said second means no longer storing said first vehicle car presencesignal or (d) said third means no longer storing said second vehicle carpresence signal, during the time said vehicle is within said givenvehicle control block, for inhibiting the provision of said vehiclecontrol signal for said vehicle within said given vehicle control block.3. The combination claimed in claim 2 wherein said first vehicle cartransmits a signal at a frequency f1 and said second vehicle cartransmits a signal at a frequency f2, which is different than saidfrequency f1; and said second means stores said first vehicle carpresence signal in response to said first means sensing the transmissionof said signal at said frequency f1, and said third means stores saidsecond vehicle car presence signal in response to said first meanssensing the transmission of said signal at said frequency f2.
 4. In avehicle control system wherein a vehicle travels along a vehicle travelpath divided into a plurality of vehicle control blocks, the combinationcomprising: first means for continuously sensing the presence of saidvehicle within a first vehicle control block; second means for storing afirst vehicle presence signal in response to said sensing by said firstmeans; third means in a second vehicle control block for continuouslysensing the presence of a vehicle within said second vehicle controlblock; fourth means located in said second vehicle control block andresponsive to said sensing by said third means for providing a secondvehicle presence signal, and said second means discontinuing the storageof said first vehicle presence signal in response to the provision ofsaid second vehicle presence signal; fifth means for providing a vehiclecontrol signal for another vehicle in a third vehicle control block inresponse to said second means no longer storing said first vehiclepresence signal; sixth means for providing a vehicle control signal forsaid vehicle within said first vehicle control block in response to saidfourth means no longer providing said second vehicle presence signal;and means for inhibiting the provision of said vehicle control signalfor said vehicle within said first vehicle control block in response toeither one of said first means no longer sensing the presence of saidvehicle within said first vehicle control block or said second means nolonger storing said first vehicle presence signal during the time saidvehicle is within said first vehicle control block.
 5. The combinationclaimed in claim 4 wherein said second means comprises a first bistableelement which is set to a first bistable state in response to saidsensing by said first means, and which remains in said first bistablestate until being set to a second bistable state in response to thesensing of the presence of said vehicle within a third vehicle controlblock.
 6. The combination claimed in claim 5 wherein said fourth meansincludes a second bistable element which is set to a first bistablestate in response to said sensing by said fourth means and which remainsin said first bistable state until being set to a second bistable statein response to the sensing of the presence of said vehicle within athird vehicle control block.
 7. In a vehicle control system wherein avehIcle includes at least first and second vehicle cars, and saidvehicle travels along a vehicle travel path divided into a plurality ofvehicle control blocks, the combination comprising: first means forcontinuously sensing the presence of said first and second vehicle carswithin a first vehicle control block; second means for storing a firstvehicle car presence signal in response to said first means sensing thepresence of said first vehicle car within said first vehicle controlblock; third means for storing a second vehicle car presence signal inresponse to said first means sensing the presence of said second vehiclecar within said first vehicle control block; fourth means in a secondvehicle control block for sensing the presence of said first and secondvehicle cars within said second vehicle control block; fifth meanslocated in said vehicle control block and responsive to said fourthmeans no longer sensing the presence of said first and second vehiclecars for providing a control signal for said first vehicle controlblock; sixth means located in said first vehicle control block forgenerating a vehicle control signal for a vehicle within said firstvehicle control block in response to said fifth means providing saidcontrol signal for said first vehicle control block; and means forpreventing the generation of said vehicle control signal for vehicleswithin said first vehicle control block in response to any one of (a)said first means no longer sensing the presence of said first and secondvehicle cars within said first vehicle control block or (b) said secondmeans no longer storing said first vehicle car presence signal or (c)said third means no longer storing said second vehicle car presencesignal, during the time said vehicle is within said first vehiclecontrol block.
 8. The combination claimed in claim 7 wherein said firstvehicle car transmits a signal at a frequency f1 and said second vehiclecar transmits a signal at a frequency f2 which is different than f1; andsaid second means stores said first vehicle car presence signal inresponse to said first means sensing the transmission of said signal atfrequency f1 and said third means stores said second vehicle carpresence signal in response to said first means sensing the transmissionof said signal at frequency f2.
 9. A method of controlling the movementof a vehicle along a vehicle travel path divided into a plurality ofvehicle control blocks, wherein said vehicle''s movement through a givenvehicle control block is controlled by a provided vehicle controlsignal, said method comprising the steps of: continuously sensing thepresence of said vehicle within said given vehicle control block;storing a vehicle presence signal in response to said sensing thepresence of said vehicle within said given vehicle control block;providing said vehicle control signal in response to sensing the absenceof a vehicle in at least the vehicle control block succeeding said givenvehicle control block; and preventing the provision of said vehiclecontrol signal in response to either one of no longer sensing thepresence of said vehicle in said given vehicle control block or notstoring said vehicle presence signal during the time said vehicle iswithin said given vehicle control block.
 10. A method of controlling themovement of a vehicle along a vehicle travel path divided into aplurality of vehicle control blocks, and said vehicle includes at leastfirst and second vehicle cars, with said vehicle''s movement through agiven vehicle control block being controlled by a provided vehiclecontrol signal, said method comprising the steps of: continuouslysensing the presence of said first and second vehicle cars within saidgiven vehicle control block; storing first and second vehicle carpresence signals in response to said sensing the presence of said firstand second vehicle cars, respectively, withIn said given vehicle controlblock; providing said vehicle control signal in response to sensing theabsence of a vehicle in the succeeding vehicle control block concurrentwith continuously sensing the presence of said first and second vehiclecars within said given vehicle control block during the time the firstand second vehicle cars presence signals are stored; discontinuing thestorage of said first and second vehicle car presence signals inresponse to sensing the presence of said first and second vehicle cars,respectively in said succeeding vehicle control block; providing avehicle control block unoccupied signal to the preceding vehicle controlblock in response to the discontinuance of the storage of said first andsecond vehicle car presence signals; and preventing the generation ofsaid vehicle control signal for said given vehicle control block inresponse to either one of no longer sensing the presence of said firstand second vehicle cars within said given vehicle control block or notstoring said first and second vehicle car presence signals during thetime said vehicle is within said given vehicle control block.